Cisco Systems 3750E Enabling EtherChannel Guard, Spanning-tree backbonefast Enable BackboneFast

Chapter 20 Configuring Optional Spanning-Tree Features

Configuring Optional Spanning-Tree Features

Note If you use BackboneFast, you must enable it on all switches in the network. BackboneFast is not supported on Token Ring VLANs. This feature is supported for use with third-party switches.

You can configure the BackboneFast feature for rapid PVST+ or for the MSTP, but the feature remains disabled (inactive) until you change the spanning-tree mode to PVST+.

Beginning in privileged EXEC mode, follow these steps to enable BackboneFast. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	spanning-tree backbonefast	Enable BackboneFast.
Step 3
	end	Return to privileged EXEC mode.
Step 4
	show spanning-tree summary	Verify your entries.
Step 5
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To disable the BackboneFast feature, use the no spanning-tree backbonefast global configuration command.

Enabling EtherChannel Guard

You can enable EtherChannel guard to detect an EtherChannel misconfiguration if your switch is running PVST+, rapid PVST+, or MSTP.

Beginning in privileged EXEC mode, follow these steps to enable EtherChannel guard. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	spanning-tree etherchannel guard	Enable EtherChannel guard.
	misconfig
Step 3
	end	Return to privileged EXEC mode.
Step 4
	show spanning-tree summary	Verify your entries.
Step 5
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To disable the EtherChannel guard feature, use the no spanning-tree etherchannel guard misconfig global configuration command.

You can use the show interfaces status err-disabledprivileged EXEC command to show which switch ports are disabled because of an EtherChannel misconfiguration. On the remote device, you can enter the show etherchannel summary privileged EXEC command to verify the EtherChannel configuration.

After the configuration is corrected, enter the shutdown and no shutdown interface configuration commands on the port-channel interfaces that were misconfigured.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		20-17